BCX-34 is an experimental drug developed by BioCryst Pharmaceuticals Inc., and is being evaluated for use in the treatment of T-cell mediated disases. It has been tested extensively in animals to show that it is safe. Oral BCX-34 has been tested on 3 patients in an initial study to evaluate its safety. During the administration of a single oral dose and a 5 day oral course, no drug related adverse events were noted. This will be the first long term study investigating the effects of this drug in humans. The purpose of this trial is to determine the most effective and least toxic dose of medication needed for a therapeutic response. This will be measured by evaluating levels of drug in the blood and urine, monitoring blood counts for potential abnormalities and assessing the response of the skin and other organs to therapy.